Inliners International Forums General Discussion Hi Performance Piston pin wall thickness

Wanted to bounce something off you guys.

Got a set of lightly used boost pistons for my drag build. Looks like the pin is a Ford FE 0.875" diameter, floating. The wall thickness is 0.090"
For a blown application, this seems a bit on the light side.

Anybody else feel queasy about that wall thickness?

Blown Alcohol rail. 6-71 BDS, Enderle Alcohol Bug, R&R aluminum rods.

CJ

You usually go the other direction when the HP level goes up and use a thicker wall wrist pin. The wrist pin actually gets oval shaped under load, and a .090" wall pin is only for use with ultra light pistons and lower HP and RPM apps. I have built and raced many high HP nitrous and blown engines and a .187" taper wall pin is the common type to use in those builds.

That was my thought on this. As I said, .090" seems mighty light. RPM isn't going to be much of an issue with the slant. We are limiting it to 7k.

We'll work through this. The roller cam won't be delivered for another month. Can't get the block mocked up until then, so plenty of time to find something appropriate. We had been talking about a tapper wall pin.

Thanks for replying Scott. Sometimes I think I'm overly paranoid about the bits and pieces I put in my engines. Of course, I haven't scattered one in a long time.

CJ

Sure CJ, I have always been paranoid of thinwall wrist pins, especially with heavy pistons. Even the thick wall pins flex more than you think they do. When using blown or other forced induction power adders, thicker is always better, because it starts becoming all about durability and longevity at that point, not how light you can make something.